Vibrating screen spring



Dec. 27,1938. H. L. STRUBE VIBRATING SCREEN SPRING Filed Au 8', 1936 2Sheets-Sheet l H. L. STRUBE v VIBRATING SCREEN SPRING Filed Aug. 8, 19362 Sheets-Sheet 2 I7Vez for flaw/y Z. jiraie Patented Dec. 27,1938 IUNiTED STATES,

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. amaze vmaa'rnsa SCREEN srmuc Harry L. Strube, Philadelphia, Pa,assignor to Link-Belt Company, Chicago, 111., a corporation of IllinoisApplication August 8, 1936, Serial No. 94,951

3 Claims.

tudinally extended plane.

Another purpose is the provision of improved; flexible supporting meansinterposed between the screen frame and its supporting base, adapt-ed topermit or guide vibration. of the screen, while limiting toa minimum thepower required for said vibration.

Another purpose is the elimination of dead spots or areas in the screen.:20 Another purpose is the prevention of the vibra=,

tion and power absorbing effect inherent in such flexible screensupporting means as spirally coiled springs.

Other objects will appear from time to time in the course of thespecification and'claims.

My invention is illustrated more or less diagrammatically in theaccompanying drawings, 1 wherein:

Figure 1 is aside elevation;

Figure 2 is an end view; with parts broken away and parts in section;

Figure 3 is a side elevation of .a variant form;

Figure 4 is a partial end view of said form;

Figure 5 is a partial side view of another variant form; V

Figure 6 is a partial variant form;

Figure 7 is a partial variant form; and v Figure 8 is a section on theline 8-8 of Figure '7.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings, I' generally indicates a side of a base framemember which may 45 be of any suitable material, but is here indicatedas of wood. It may be supported on any suitable endsupport herein shownas! and 3.

Obviously the screen may be mounted in any sort of support or on anyfoundation, and the members I, 2 and 3 here serve as suggestions merelyof one form of support for the screen. The invention is not limited tothis or to any other support nor to the details of construction shown,and any material desirable may be used. A block 4 may be positionedbetween each of the side view of another side view of yet another thescreen frame, vertically and along a longihorizontal members I and thescreen, as shown in Figure 3, or the metallic brackets ta, as shown inFigures 1 and 2, may be employed, which include upstanding spacingmembers db,- which spacethe horizontalportion do from the structural orbase member.

In the particular form here shown the screen proper comprises side framemembers 5 which may be joined by any suitable cross members, if desired,and which are shown as spaced and 10 secured by transverse frame members6. One ,or more members 1 may be supported uponor attached to themembers 6. The screen cloth 8 rests upon these members. Removableclamping plates 9 are secured by bolts I0 and nuts H, or

' otherwise, and hold the screen cloth in place.

The side members 5 are preferably provided with flanges I2 which extendoutwardly.

Secured to and preferably mounted upon the I upper edgeof the sidemembers 5, for example upon the flanges I2, is an out-of-balance rotorI3 which carries a pulley l4 and may be driven by a belt or other meansl5. The invention is not limited to the particular form of vibratorymeans shown and that which appears in Figures 1 and 2 appears onlyas anillustration of the fact that vibratory means are provided.

I may for example employ a' rotor which includes an eccentriclongitudinally extending body portion l3a. Associated with the eccentricI may also employ additional eccentrics or counterweights l3b which maybe adjustable about the axis of rotation of the rotor and may beemployed either to accentuate the unbalanced effect ofthe portion l3a,or partially to balance it whereby,

as to eachscreen and for each problem, the vibration of the particularscreen may be adjusted accurately in relation to the spring supportingmeans employed therefor. The vibratory means may be provided withbrackets l6 for attachment 40 to the flange l2 or-may be otherwiseattached.

' Referring to Figures 1 and 2, I secure to the ."horizontal portion ofthe bracket do a leaf spring member generally indicated as whichincludes a. plurality of generally horizontal leaf members 5 5!, ofvarying lengths, held together and to the bracket portion 40 for exampleby bolts 53 with their lock nuts 54. 55 indicates surrounding holders orclips with securing bolts 56, adapted to hold the individual leafmembers firmly to- 50 gether, while permitting sufllcient flexure of thespring as a whole to enable it to perform its function.

The upper leaf 51, shown as separated in two parts as'at 58, has ends 59at the ends of arcuate 55 or bowed portions 60. The reversely extendingend portions 59 engage and support brackets which include an upperportion GI and a side portion 62, both of which may be welded orotherwise secured to the screen side frame member 5. Preferably thelower end of the member 62 extends slightly below the edge of the sidemember, say at 63. A clamp plate 64 may be employed to clamp the partstogether, as by the bolt' 65 and its nuts 66. It is somewhat beveled orcut away as at 61 to permit the screen assembly to vibrate withoutcramping the spring,

and to prevent the spring from being contacted by a sharp edge.

' In the form shown in Figures 3 to 6, inclusive,

a supporting member is provided, attached to the screen and arranged toreceive the ends of the spring. This member comprises a side plate i!with an inwardly and downwardly bent flange i8 and an outwardly andlaterally bent portion i9, which portion is generally of the same sizeas the flange i2. Secured to the side plate i7, and also to the portionis are brackets 20. The plate I7 and brackets thus form in effect apartially enclosing housing for the spring ends.

In the form of the device shown generally in Figures 3 to 5, inclusive,a leaf spring 2| is provided. This spring rests upon the block 4 and issecured by bolts Zia or otherwise. The upper leaf of the spring assemblycomprises a member or members 22, provided with return curved portions23 which are flattened at their ends as at 24, bear upon the sections i9of the plates i! and are secured in place by bolts 25 or otherwise.

Retaining members 26 maybe mounted on the spring at suitable intervals-The ends of the spring leaves adjacent the leaves 22 may extendoutwardly as at 21. This is not an essential feature but may be embodiedand has the advantage of reinforcing-the spring section-22 at the outerend of the spring. It may, of course, be omitted.

The sections it may be provided with depressions or recesses 28 at thepoint where the curved -section'23 ends. Thisis-done so that the springat the point of its movement shall not be in contact with a sharp edge.The depression 28 is made and the edge 29 is rounded. A securing plate30 is positioned adjacent the flat section 26 of the spring 22 and it isprovided with a curved edge 3! which serves the same Pu ose as thecurved portion 29. The nuts and bolts engage not the spring section 24but the upper face of the flange i9 and the lower face of the plate 30.7

The form-of the invention shown in Figure 5 differs from that shown inFigures'ii and 4 only in the fact that instead of the more or lesssemicircular curved portion 23, there is provided a generally straightportion 23' and twoshorter curved portions 28". In other words, thedevice ofFigure 5 difiers from that of Figure 3 by the shape of thecurve of the upper spring leafor member.

In the form of Figure 6 the upper spring leaf is the same as that shownin Figure 5 but instead of being mounted upon a leaf or other spring itis mounted directly upon the base member '6 so that it is secured to afixed base instead of being secured to a moving base or spring.- Whenthe form of'the device. shown in Figure 6 is used, the spring may begiven any desired length. It may be shorter or longer. As shown,although it conforms in shape to theupper spring member of Figure 5, itissomewhat shorter. 1

Inthe form of the' device shown in Figure '1,

being held in position the screen as a whole yieldin permitting a.movement in mitted the generally the spring arrangement is generally thesam: as that shown in Figures 3 and 4 except for the means by which theend of the spring membei 22 is secured .to the screen section. A'brackeimember 32 is secured to the side member 5 01 the screen by bolts, bywelding or otherwise. A: shown it comprises a downwardly dependingportion 33 which corresponds in shape to the shape of the screen frameand it comprises an upper enlarged portion 34 which is split to providea top section 35 and a lower section 36. Within the slot or grooveformed between these two sections the upper portion 24 of the spring 22is received. The spring is provided additionally with a downwardly bentend 31' which fits against the rear of the bracket and is'held in placeby one or more bolts 38. It will be noticed that the ends of the uppersection 35 are curved as at 39 and that the corresponding or oppositelyplaced edges of the lower section 36 are curved as at so that the springin its fle'xure is in contact with rounded surfaces rather than withangular surfaces which might damage it.

It will be realized that whereas I have described and illustrated apractical and operative device, nevertheless many changes may be made inthe size, shape, number and disposition of parts without departing fromthe spirit of my invention. I therefore wish my description and drawingsto be taken as in a broad sense illustrative or diagrammatic rather thanas limiting me to the precise showing.

The use and operation of this invention are as follows:

The screen may be assembled generally as shown in the various forms Itmay be positioned horizontally or at an angle to the horizontal. Whenthe out-of-balance rotor or other vibratory means is put in motion,vibrates. The leaf springs are flexible and permit movement of thescreen as a whole. The connection of the leaf springs to the screenframe is by the flexible member 23, for example, as shown in Figures 3and'l, which particular form this comprises an extension of the spring,but it might be a separate yielding member which does not structurallyform apart of one pf the spring leaves. The construction shown,

efiect of the leaf spring itself a further yielding and movementpermitted by the flexible connection, whether that connection comprisesa portion of the spring, a portion of the leaf of a spring, or anentirely additional member.

In theform shown in Figure 5, the flexible connection 23' operatesgenerally the same as the flexible connection 23 of Figures 3 and 7. Asomewhat diflerentshape is Otherwise its operation is generally the sameand it permits a movement and a to that permitted by the leaf springsalone.

In' the form shown in Figure 6, there is no multiple leaf spring. Thesingle member 22comprises the spring and it is, in a sense, a singleleaf or cantilever spring. The flexible section 23 is the same ascarries out the same function, namely, that of flat portion. 22..

illustrated herewith therefore, provides in addition to the that .shownin Figure Bind" is a curved extension to the upper spring leaf and I theleaf springs, a

given to the spring.

yielding additional additionto that perscreen, it should.- be kept inmind that the weight of the screen frame as a whole is mounted entirelyIn whatever form the device appears, it preferably comprises a generallyelongated spring member and a flexible yielding or spring connectionbetwen the end of that member and the screen. In the preferred form thisflexible connection comprises what may be generally called a U-shapedspring member. This has the importantadvantage of providing a sharp.quick reaction as the screen is vibrated. In the particular form shownin Figures 5 and 6, the por tion 23' is shown as rectilinear, andgenerally perpendicular to the portions 22 and 24.

Under some circumstances I may even omit the upper arm 24 of the membershown in Figures 5 and 6, although I find the structure shown in thosefigures practical and satisfactory. I have determined from experiencethat spring structures such as those herein shown and described are, intheir sharpness and quickness of reaction and in their generalemcie'ncy, much superior to some of the other connecting means, such asrubber blocks, or spiral or coil springs. The shock absorbing or dampingaction of a spiral spring is a sharpcontrast to the snap and sharp,quick action of the springs herein described and claimed: The result isa very substantial increase in screening eiliciency and capacity, whichI have observed in actual use.

For most purposes the multiple leaf spring, together with thegenerallyu-shaped member is preferable for manufacturing reasons, andbecause of 'the added resiliency in the leaf spring which permits it toabsorb and to dampen the severest action due to any extreme vibrationset. up by rotation of the out-of-balance rotor. For most purposes,therefore, the complete spring assembly is preferable, which not onlyimproves the screen action but reduces the amount of vibrationtransmitted to the supporting structure.

In considering the general applicability of the upon the leaf springs ateach side of the frame, which largely prevent the transmission ofvibration to the screen base I, while providing a very satisfactoryvibration of the screen. I find it practical to position the vibratingmember over the center of the support of the screen, although this maybe varied, and otherwise located. I

also'find it important to employ a' counter- 'weighted'or unbalancedrotating member to impart vibration to the screen boxas a whole, whichmember is preferably adjustable in such fashion as to permit a variationor control of the amplitudeof vibration given to .the screen by rotationof the unbalanced member. Thus, by employing an unbalanced rotor havinga fixed eccentric portion "4 and adjustable eccentric portions lib,

I can adjust the eccentricity or the throw of llb to suit the particularsprings employed, materialscreepemorbotmsothatthespringswill give therequired vibration for the particular job or material.

as the various drawings show. I may considerably nry the shape" and thedisposition of the and the details of the securing means.

factory, and in connection with them employ an arcuately recurved endportion for the top leaf 51, which arcuately recurved end portionterminates in a horizontal portion 59 parallel with the body of thespring. Preferably such a portion is employed at each end of the spring.The clamping brackets 6| and 62 provide a firm abutment and the springend 59 is clamped between the bracket member BI and the clamp blade SI.

By employing a single bend or turn of spring stock at each end of thespring body, I provide a spring member which permits the rotation of therotor to impart its centrifugal vibration uniformly to the spring as awhole, with no dead spots and little variation in the amplitude of thevibration of the individual screen cloth areas. I also find that theemployment of this type of spring greatly reduces the loss of efficiencywhich is inherent in the employment of the spirally coiled springs, orin the employment of rubber bushings or other flexure permitting meanswhich,

unfortunately, are ideally adapted to dampen vibration. The absorptionof vibration in rubber bushings, spiral or coil springs, and the like isa" waste which is avoided in my form of screen.

I may employ two quarter-elliptical springs at each side of the screenbox. This may be useful in long screens and the modification is soclearas not to involve the necessity of separate illustration. Thus, inFigure 6, one is shown ateach end of each side of the screen box. Anyof. the springs herein shown could be thus modified, with aquarter-elliptic spring at each corner of the box, mounted on thesupport 'I, two on each side.

I claim:

1. In a vibratory screen, a base, a screen frame, and supporting meansfor the screen frame, including leaf springs interposed between thescreen frame andvthe base, each said leaf spring includthe screen box,said springs including generally" U-shaped members comprising loops ofapproximately 180 degrees curvature, said U-shaped members being securedto the screen box at their gee ends, and means'for vibrating the screenside of said screen box, said springs supporting said box and beingmounted upon the base and secured at their outer ends to the screen box,said springs including generally U-shaped members comprising loops ofapproximately 180 degrees 3. m a vibratory screen assembly, in'combina-.'tion, a screen box, abase, leaf springs on either curvature; said-U-shaped members being securedtothe screen box at their free ends, andmeans for vibrating the screen box, each said U-shaped member beingintegral with a spring leaf.

many 1..

